R-T-B based rare earth magnets containing a rare earth element R, a transition metal element T such as Fe or Co and boron B have superior magnetic properties. Numerous studies have conventionally been carried out in order to improve the residual magnetic flux density (Br) and coercive force (HcJ) of R-T-B based rare earth magnets (see, the following Patent Literature 1 and Patent Literature 2). R-T-B based rare earth magnets are hereinafter sometimes referred to as “R-T-B based magnet”.